/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2015 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.exist.xquery;
import java.util.ArrayList;
import java.util.List;
import org.exist.Namespaces;
import org.exist.dom.QName;
import org.exist.xquery.Constants.Comparison;
import org.exist.xquery.Constants.StringTruncationOperator;
import org.exist.xquery.parser.XQueryAST;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.StringValue;
import org.exist.xquery.value.Type;
public class FunctionFactory {
public static final String ENABLE_JAVA_BINDING_ATTRIBUTE = "enable-java-binding";
public static final String PROPERTY_ENABLE_JAVA_BINDING = "xquery.enable-java-binding";
public static final String DISABLE_DEPRECATED_FUNCTIONS_ATTRIBUTE = "disable-deprecated-functions";
public static final String PROPERTY_DISABLE_DEPRECATED_FUNCTIONS = "xquery.disable-deprecated-functions";
public static final boolean DISABLE_DEPRECATED_FUNCTIONS_BY_DEFAULT = false;
public static Expression createFunction(XQueryContext context, XQueryAST ast, PathExpr parent, List<Expression> params) throws XPathException {
QName qname = null;
try {
qname = QName.parse(context, ast.getText(), context.getDefaultFunctionNamespace());
} catch(final XPathException xpe) {
xpe.setLocation(ast.getLine(), ast.getColumn());
throw xpe;
}
return createFunction(context, qname, ast, parent, params);
}
public static Expression createFunction(XQueryContext context, QName qname, XQueryAST ast, PathExpr parent, List<Expression> params) throws XPathException {
return createFunction(context, qname, ast, parent, params, true);
}
/**
* Create a function call.
*
* This method handles all calls to built-in or user-defined
* functions. It also deals with constructor functions and
* optimizes some function calls like starts-with, ends-with or
* contains.
*/
public static Expression createFunction(XQueryContext context, QName qname, XQueryAST ast, PathExpr parent, List<Expression> params,
boolean optimizeStrFuncs) throws XPathException {
final String local = qname.getLocalPart();
final String uri = qname.getNamespaceURI();
Expression step = null;
if (optimizeStrFuncs && (Namespaces.XPATH_FUNCTIONS_NS.equals(uri) || Namespaces.XSL_NS.equals(uri))) {
if("starts-with".equals(local)) {
step = startsWith(context, ast, parent, params);
} else if("ends-with".equals(local)) {
step = endsWith(context, ast, parent, params);
} else if("contains".equals(local)) {
step = contains(context, ast, parent, params);
} else if("equals".equals(local)) {
step = equals(context, ast, parent, params);
}
//Check if the namespace belongs to one of the schema namespaces.
//If yes, the function is a constructor function
} else if (uri.equals(Namespaces.SCHEMA_NS) ||
uri.equals(Namespaces.XPATH_DATATYPES_NS)) {
step = castExpression(context, ast, params, qname);
//Check if the namespace URI starts with "java:". If yes, treat
//the function call as a call to an arbitrary Java function.
} else if (uri.startsWith("java:")) {
step = javaFunctionBinding(context, ast, params, qname);
}
//None of the above matched: function is either a built-in function or
//a user-defined function
if (step == null) {
step = functionCall(context, ast, params, qname);
}
return step;
}
/**
* starts-with(node-set, string)
*/
private static GeneralComparison startsWith(XQueryContext context,
XQueryAST ast, PathExpr parent, List<Expression> params) throws XPathException {
if (params.size() < 2) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Function starts-with() requires two or three arguments");
}
if (params.size() > 3) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Function starts-with() requires two or three arguments");
}
final PathExpr p0 = (PathExpr) params.get(0);
final PathExpr p1 = (PathExpr) params.get(1);
if (p1.getLength() == 0) {
throw new XPathException(ast.getLine(), ast.getColumn(),
"Second argument of starts-with() is empty");
}
final GeneralComparison op = new GeneralComparison(context, p0, p1,
Comparison.EQ, StringTruncationOperator.RIGHT);
op.setLocation(ast.getLine(), ast.getColumn());
//TODO : not sure for parent -pb
context.getProfiler().message(parent, Profiler.OPTIMIZATIONS,
"OPTIMIZATION", "Rewritten start-with as a general comparison with a right truncations");
if (params.size() == 3) {
op.setCollation((Expression) params.get(2));
}
return op;
}
/**
* ends-with(node-set, string)
*/
private static GeneralComparison endsWith(XQueryContext context, XQueryAST ast,
PathExpr parent, List<Expression> params) throws XPathException {
if (params.size() < 2) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Function ends-with() requires two or three arguments");
}
if (params.size() > 3) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Function ends-with() requires two or three arguments");
}
final PathExpr p0 = (PathExpr) params.get(0);
final PathExpr p1 = (PathExpr) params.get(1);
if (p1.getLength() == 0) {
throw new XPathException(ast.getLine(), ast.getColumn(),
"Second argument of ends-with() is empty");
}
final GeneralComparison op = new GeneralComparison(context, p0, p1, Comparison.EQ, StringTruncationOperator.LEFT);
//TODO : not sure for parent -pb
context.getProfiler().message(parent, Profiler.OPTIMIZATIONS,
"OPTIMIZATION", "Rewritten ends-with as a general comparison with a left truncations");
op.setLocation(ast.getLine(), ast.getColumn());
if(params.size() == 3) {
op.setCollation((Expression) params.get(2));
}
return op;
}
/**
* contains(node-set, string)
*/
private static GeneralComparison contains(XQueryContext context, XQueryAST ast,
PathExpr parent, List<Expression> params) throws XPathException {
if (params.size() < 2) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Function contains() requires two or three arguments");
}
if (params.size() > 3) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Function contains() requires two or three arguments");
}
final PathExpr p0 = (PathExpr) params.get(0);
final PathExpr p1 = (PathExpr) params.get(1);
if (p1.getLength() == 0) {
throw new XPathException(ast.getLine(), ast.getColumn(),
"Second argument of contains() is empty");
}
final GeneralComparison op = new GeneralComparison(context, p0, p1,
Comparison.EQ, StringTruncationOperator.BOTH);
//TODO : not sure for parent -pb
context.getProfiler().message(parent, Profiler.OPTIMIZATIONS,
"OPTIMIZATION", "Rewritten contains() as a general comparison with left and right truncations");
op.setLocation(ast.getLine(), ast.getColumn());
if (params.size() == 3) {
op.setCollation((Expression) params.get(2));
}
return op;
}
/**
* equals(node-set, string)
*/
private static GeneralComparison equals(XQueryContext context, XQueryAST ast,
PathExpr parent, List<Expression> params) throws XPathException {
if (params.size() < 2) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Function equals() requires two or three arguments");
}
if (params.size() > 3) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Function equals() requires two or three arguments");
}
final PathExpr p0 = (PathExpr) params.get(0);
final PathExpr p1 = (PathExpr) params.get(1);
if (p1.getLength() == 0) {
throw new XPathException(ast.getLine(), ast.getColumn(),
"Second argument of equals() is empty");
}
final GeneralComparison op = new GeneralComparison(context, p0, p1,
Comparison.EQ, StringTruncationOperator.EQUALS);
//TODO : not sure for parent -pb
context.getProfiler().message(parent, Profiler.OPTIMIZATIONS,
"OPTIMIZATION", "Rewritten contains() as a general comparison with no truncations");
op.setLocation(ast.getLine(), ast.getColumn());
if (params.size() == 3) {
op.setCollation((Expression) params.get(2));
} else {
op.setCollation(new StringValue("?strength=identical"));
}
return op;
}
private static CastExpression castExpression(XQueryContext context,
XQueryAST ast, List<Expression> params, QName qname) throws XPathException {
if (params.size() != 1) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Wrong number of arguments for constructor function");
}
final Expression arg = params.get(0);
final int code = Type.getType(qname);
final CastExpression castExpr = new CastExpression(context, arg, code, Cardinality.ZERO_OR_ONE);
castExpr.setLocation(ast.getLine(), ast.getColumn());
return castExpr;
}
private static JavaCall javaFunctionBinding(XQueryContext context,
XQueryAST ast, List<Expression> params, QName qname) throws XPathException {
//Only allow java binding if specified in config file <xquery enable-java-binding="yes">
final String javabinding = (String) context.getBroker().getConfiguration()
.getProperty(PROPERTY_ENABLE_JAVA_BINDING);
if(javabinding == null || !"yes".equals(javabinding)) {
throw new XPathException(ast.getLine(), ast.getColumn(),
"Java binding is disabled in the current configuration (see conf.xml)." +
" Call to " + qname.getStringValue() + " denied.");
}
final JavaCall call = new JavaCall(context, qname);
call.setLocation(ast.getLine(), ast.getColumn());
call.setArguments(params);
return call;
}
private static Function functionCall(XQueryContext context,
XQueryAST ast, List<Expression> params, QName qname) throws XPathException {
final Function fn;
final String uri = qname.getNamespaceURI();
final Module module = context.getModule(uri);
if (module != null) {
//Function belongs to a module
if (module.isInternalModule()) {
fn = getInternalModuleFunction(context, ast, params, qname, module);
} else {
//Function is from an imported XQuery module
fn = getXQueryModuleFunction(context, ast, params, qname, module);
}
} else {
fn = getUserDefinedFunction(context, ast, params, qname);
}
return fn;
}
/**
* Gets a Java function from an Java XQuery Extension Module
*/
private static Function getInternalModuleFunction(XQueryContext context,
XQueryAST ast, List<Expression> params, QName qname, Module module) throws XPathException {
//For internal modules: create a new function instance from the class
FunctionDef def = ((InternalModule) module).getFunctionDef(qname, params.size());
//TODO: rethink: xsl namespace function should search xpath one too
if (def == null && Namespaces.XSL_NS.equals(qname.getNamespaceURI())) {
//Search xpath namespace
Module _module_ = context.getModule(Namespaces.XPATH_FUNCTIONS_NS);
if(_module_ != null) {
module = _module_;
qname = new QName(qname.getLocalPart(), Namespaces.XPATH_FUNCTIONS_NS, qname.getPrefix());
def = ((InternalModule) module).getFunctionDef(qname, params.size());
}
}
if (def == null) {
final List<FunctionSignature> funcs = ((InternalModule) module).getFunctionsByName(qname);
if (funcs.isEmpty()) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Function " + qname.getStringValue() + "() " +
" is not defined in module namespace: " + qname.getNamespaceURI());
} else {
final StringBuilder buf = new StringBuilder();
buf.append("Unexpectedly received ");
buf.append(params.size());
buf.append(" parameter(s) in call to function ");
buf.append("'");
buf.append(qname.getStringValue());
buf.append("()'. ");
buf.append("Defined function signatures are:\r\n");
for (final FunctionSignature sig : funcs) {
buf.append(sig.toString()).append("\r\n");
}
throw new XPathException(ast.getLine(), ast.getColumn(), ErrorCodes.XPST0017, buf.toString());
}
}
if (((Boolean) context.getBroker().getConfiguration()
.getProperty(PROPERTY_DISABLE_DEPRECATED_FUNCTIONS)).booleanValue() &&
def.getSignature().isDeprecated()) {
throw new XPathException(ast.getLine(), ast.getColumn(),
"Access to deprecated functions is not allowed. Call to '" + qname.getStringValue() + "()' denied. " + def.getSignature().getDeprecated());
}
final Function fn = Function.createFunction(context, ast, def);
fn.setArguments(params);
fn.setASTNode(ast);
return new InternalFunctionCall(fn);
}
/**
* Gets an user defined function from the XQuery
*/
private static FunctionCall getUserDefinedFunction(XQueryContext context, XQueryAST ast, List<Expression> params, QName qname) throws XPathException {
final FunctionCall fc;
final UserDefinedFunction func = context.resolveFunction(qname, params.size());
if (func != null) {
fc = new FunctionCall(context, func);
fc.setLocation(ast.getLine(), ast.getColumn());
fc.setArguments(params);
} else {
//Create a forward reference which will be resolved later
fc = new FunctionCall(context, qname, params);
fc.setLocation(ast.getLine(), ast.getColumn());
context.addForwardReference(fc);
}
return fc;
}
/**
* Gets an XQuery function from an XQuery Module
*/
private static FunctionCall getXQueryModuleFunction(XQueryContext context,
XQueryAST ast, List<Expression> params, QName qname, Module module) throws XPathException {
final FunctionCall fc;
final UserDefinedFunction func = ((ExternalModule) module).getFunction(qname, params.size(), context);
if (func == null) {
// check if the module has been compiled already
if (module.isReady()) {
throw new XPathException(ast.getLine(), ast.getColumn(),
ErrorCodes.XPST0017, "Function " + qname.getStringValue() +
"() is not defined in namespace '" + qname.getNamespaceURI() + "'");
// If not, postpone the function resolution
// Register a forward reference with the root module, so it gets resolved
// when the main query has been compiled.
} else {
fc = new FunctionCall(((ExternalModule) module).getContext(), qname, params);
fc.setLocation(ast.getLine(), ast.getColumn());
if(((ExternalModule) module).getContext() == context) {
context.addForwardReference(fc);
} else {
context.getRootContext().addForwardReference(fc);
}
}
} else {
fc = new FunctionCall(context, func);
fc.setArguments(params);
fc.setLocation(ast.getLine(), ast.getColumn());
}
return fc;
}
/**
* Wrap a function call into a user defined function.
* This is used to handle dynamic function calls or partial
* function applications on built in functions.
*
* @param context
* @param call the function call to be wrapped
* @return a new function call referencing an inline function
* @throws XPathException
*/
public static FunctionCall wrap(XQueryContext context, Function call) throws XPathException {
final int argCount = call.getArgumentCount();
final QName[] variables = new QName[argCount];
final List<Expression> innerArgs = new ArrayList<Expression>(argCount);
final List<Expression> wrapperArgs = new ArrayList<Expression>(argCount);
final FunctionSignature signature = call.getSignature();
// the parameters of the newly created inline function:
final List<SequenceType> newParamTypes = new ArrayList<SequenceType>();
final SequenceType[] paramTypes = signature.getArgumentTypes();
for (int i = 0; i < argCount; i++) {
final Expression param = call.getArgument(i);
wrapperArgs.add(param);
QName varName = new QName("vp" + i);
variables[i] = varName;
final VariableReference ref = new VariableReference(context, varName);
innerArgs.add(ref);
// copy parameter sequence types
// overloaded functions like concat may have an arbitrary number of arguments
if (i < paramTypes.length)
{newParamTypes.add(paramTypes[i]);}
else
// overloaded function: add last sequence type
{newParamTypes.add(paramTypes[paramTypes.length - 1]);}
}
final SequenceType[] newParamArray = newParamTypes.toArray(new SequenceType[newParamTypes.size()]);
final FunctionSignature newSignature = new FunctionSignature(signature);
newSignature.setArgumentTypes(newParamArray);
final UserDefinedFunction func = new UserDefinedFunction(context, newSignature);
for (final QName varName: variables) {
func.addVariable(varName);
}
call.setArguments(innerArgs);
func.setFunctionBody(call);
final FunctionCall wrappedCall = new FunctionCall(context, func);
wrappedCall.setArguments(wrapperArgs);
return wrappedCall;
}
}